Here's where you start:
Panther's Beginners Pack
This is a complilation of books on a variety of pagan paths. Brought to you once again by Smiling Panther's Den.
Or you could start here:
Ceisiwr Serith's Handy Dandy Wicca Starter Kit
This was taken from an article posted on the Pagan Message Boards. Cei is a respected author of pagan books.
If you notice, most of these books overlap. This just shows what great books they are.
Unfortunately, not all the books you find will be good:
Trash Heap
Earth Power by Scott Cunningham
Green Witchcraft Series by Ann Moura
A Pagan Book of Prayer by Ceisiwr Serith
Practical Candleburning Rituals by Ray Buckland
Exploring Wicca by Lady Sabrina
Advanced Candle Magick by Ray Buckland
Magical Aromatherapy by Scott Cunningham
Celtic Myth and Magick by Edain McCoy
Through the Gates of Death by Dion Fortune
Northern Magic by Edred Thorsson
Signs, Symbols, and Omens by Ray Buckland
Witchcraft for Tomorrow by Doreen Valiente
Spell Crafts by Scott Cunningham and David Harrington